Hakata Station to Kurosawa Onsen

Hi there!

I assume that you mean Kurokawa Onsen in Kyushu. Unfortunately there are no train tracks going there all the way. The best way to get there with the JR Pass is to take the train to Aso station (the same station if you want to visit mount Aso) and take an express bus from there.

The train to Aso takes about 122 Minutes, the bus would add at least an other hour.
I would recommend reading this website for more access information.

I hope this helps!
Daniel